Cossus cossus is spread almost all over the palearctic region and in North-Africa. It has a biennial or triennial cycle, the period of maximum adult emergence being the months of June and July.
At the larval-stage it attacks almost all the hardwood trees and it digs deep galleries in the trunks and branches, thus jeopardizing also, seriously, the vitality of the infested plants and degrading the commercial value of the wood.
In late years, it has spread particularly in the fruit-bearing plants and in the poplars, causing serious damages.
At present this lepidopterous is fought by using conventional insecticides. However, the particular biology of such insect renders the conventional fight method little effective.
Knowledge of the substances composing the sexual pheromone of an insect, or the determination of a mixture of substances endowed with a sexual attracting effect for a certain species, generally permits new methods of fight against the infestations of that insect species.
As is known, the female of most of Lepidoptera emits a sexual pheromone which attracts the male for coupling. The natural pheromone mixture, which generally consists of more components and is specific for each species, possesses a high volatility and spreads in the air even to a great distance.
When the pheromone mixture contacts particular senseorgans of the males (i.e., the chemoreceptive sensilla prevailingly located on the antennae) it attracts the insect towards the source.
When a mixture of substances having a similar effect is available, it is possible to prepare a trap containing the attracting mixture in a suitable composition capable of ensuring a controlled release thereof. The males of the species, coming into contact with the mixture spread in the air, are attracted towards the trap where they are captured and killed.
Use of the said traps permits mass-captures of males of the species, thereby drastically reducing the number of couplings and, by consequence, of future populations of the insect.
Another useful utilization of the traps containing sexual attractants is that of promoting a monitoring action. In fact, by detecting the number of captures in traps containing an attracting mixture and properly located in a zone probably subject to infestation, it is possible to determine, with sufficient accuracy, the limits of the infested zone and the insect population density in such zone. These data permit intervention whenever and wherever necessary by using conventional insecticides.
The monitoring action permits therefore, reduction of the number of treatments to those which are strictly required and to limit them to the zone where infestations may occur, which results in economic and environmental advantages and adversely affects the development of insect strains resistant to the insecticide utilized.
Another useful utilization of a sexual attracting mixture for insects consists in permeating an infested zone, in the mating period, with the attracting mixture. As a consequence thereof, the males of the species are no longer able to locate the females and the amount of couplings decreases, thus drastically reducing the future insect population in such zone.
As far as we know, no researches have been carried out previously on the adults of Cossus cossus with a view to identifying the pheromone or mixtures endowed with an analogous effect.